title: [Myasthenia, from the internist's point of view].
abstract: Myasthenia gravis is an autoimmune disease due to specific antibodies inducing a neuromuscular transmission defect causing muscle fatigability. If onset of the disease may be at any age, myasthenia gravis concerns mostly young adults, in majority females. The disease characteristic features are the following: ocular symptoms (ptosis or diplopia) as main initial manifestation, extension to other muscles in 80 % of the cases, variability of the deficit, effort induced worsening, successive periods of exacerbation during the disease course, severity depending on respiratory and swallowing impairment (if rapid worsening, a myasthenic crisis is to be suspected), association with thymoma in 20 % of patients and with other various autoimmune diseases, most commonly hyperthyroidism and Hashimoto's disease. Diagnosis relies on the clinical features, improvement with cholinesterase inhibitors, detection of specific autoantibodies (anti-AChR or anti-MuSK), and significant decrement evidenced by electrophysiological tests. The points concerning specifically the internist have been highlighted in this article: diagnostic traps, associated autoimmune diseases, including inflammatory myopathies that may mimic myasthenia gravis, adverse effects of medications commonly used in internal medicine, some of them inducing myasthenic syndromes. The treatment is well codified: the treatment is well codified: (1) respect of adverse drugs contra-indications, systematically use of cholinesterase inhibitors, (2) thymectomy if thymoma completed with radiotherapy if malignant, (3) corticosteroids or immunosuppressive agent in severe or disabling form, (4) intensive care unit monitoring, plasmapheresis or intravenous immunoglobulins for patients with myasthenic crisis.
authors.affiliation: Unité de pathologie neuromusculaire, service de neurologie 2, centre de référence de pathologie neuromusculaire Paris Est, hôpital de la Pitié-Salpêtrière, institut de myologie, bâtiment Babinski, 47-83, boulevard de l'Hôpital, 75651 Paris cedex 13, France. Electronic address: anne-marie.maronne.@psl.aphp.fr.
authors.forename: B
authors.initials: B
authors.lastname: Eymard
mesh_terms: D001323:Autoantibodies / Q000097:blood; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D009157:Myasthenia Gravis / Q000150:complications* / Q000175:diagnosis* / Q000628:therapy
chemical_list: D001323:Autoantibodies
keywords: Congenital myasthenic syndromes; Iatrogenic myasthenic syndromes; Lambert-Eaton syndrome; Myasthenia gravis; Myasthénie auto-immune; Syndrome de Lambert-Eaton; Syndromes myasthéniques congénitaux; Syndromes myasthéniques iatrogènes; Thymoma; Thymome